Gut microbiota, a potential cause of higher insulin sensitivity in children with Prader-Willi syndrome.

PURPOSE: Obesity is the main driving factor for comorbidities in Prader-Willi syndrome (PWS) patients due to overeating behaviors. The gut microbiota has been implicated in the etiology of obesity and associated comorbidities. The purpose of the present study was to characterize the fecal microbiota in Chinese patients with PWS and compare it to that of patients with obesity as well as healthy controls. METHODS: We conducted a cross-sectional study with 35 PWS patients (PWS), 35 patients with obesity (OB), and 35 healthy controls (HC). Metagenomic sequencing was performed in stool samples. RESULTS: The composition of the fecal microbiota in PWS patients differed from that of participants in the OB and HC groups. It was characterized by increased Akkermansia Eubacterium, Eubacterium rectale, and Roseburia intestinalis and decreased Parabacteroides and Phascolarctobacterium. Additionally, the homeostatic model assessment of insulin resistance (HOMA-IR) was lower in PWS patients than in patients with obesity. Spearman rank correlation analysis showed that Achromobacter, Acidiphilium, Xylophilus, and Frisingicoccus were significantly negatively correlated with HOMA-IR. CONCLUSION: The composition of the gut microbiota in Chinese PWS patients differed from that in patients with obesity, which might contribute to higher insulin sensitivity in PWS patients.

[The indication and surgery scope for laparoscopic extraperitoneal lymphadenectomy in locally advanced cervical cancer].

Objective: To explore the indication and surgery scope for laparoscopic extraperitoneal lymphadenectomy in locally advanced cervical cancer. Methods: Laparoscopic extraperitoneal lymphadenectomy was initially performed on patients with locally advanced cervical cancer. The results of preoperative computed tomography (CT) images and serum level of squamous cell carcinoma antigen (SCC-Ag) were analyzed, and the diagnostic efficiencies of the minimum axial diameter (MAD) of lymph node on CT≥0.5 cm, ≥1.0 cm, serum level of SCC-Ag alone or combined to predict the extraperitoneal lymph node metastases were compared. The high-risk factors of common iliac lymph node (CILN) and para-aortic lymph node (PALN) metastases were also analyzed. Results: The lymph node metastasis rate of 81 patients who received the laparoscopic extraperitoneal lymphadenectomy was 59.3% (48/81). The CILN and/or PALN metastasis rate was 24.7%(20/81), and among them, the MAD of CILN and/or PALN ≥0.5 cm on CT images were in only 7 patients. The threshold of SCC-Ag for evaluating lymph node metastasis was 4.8 ng/ml. The accuracy, specificity and Youden index of SCC-Ag≥4.8+ MAD≥1.0 cm group for predicting lymph node metastasis were 78.3%, 100% and 0.6, respectively, and were significantly higher than 57.9%, 12.1% and 0.1 of MAD≥0.5 cm group, 71.1%, 75.8% and 0.4 of MAD≥1.0 cm group, 65.0%, 57.7% and 0.3 of SCC-Ag≥4.8 ng/ml group and 68.3%, 65.4% and 0.4 of SCC-Ag≥4.8 ng/ml+ MAD≥0.5 cm group (P<0.05). All of the 21 patients in SCC-Ag≥4.8 ng/ml+ MAD≥1.0 cm group were detected to occur lymph node metastases, and the metastasis rate of CILN and/or PALN was 38.1%. While only 4 cases of 17 patients in SCC-Ag<4.8 ng/ml+ MAD<1 cm group were confirmed to occur CILN metastases. The difference of lymph node metastasis rate between these two groups was statistically significant (P<0.001). The pathological type, the number of PLN with MAD≥1.0 cm, at least one of the PLN MAD≥1.0 cm and/or MAD of CILN and/or PALN was 0.5~1.0 cm were associated with the CILN and/or PALN metastases (all P<0.05). Conclusions: Those patients with MAD≥1.0 cm+ SCC-Ag≥4.8 ng/ml and with high-risk factors of CILN and/or PALN metastases should undergo laparoscopic extraperitoneal lymphadenectomy to provide explicit guidance for the subsequent therapy. However, the incidence of lymph node metastasis of patients with SCC-Ag<4.8 ng/ml combined with MAD<1.0 cm is low, therefore these patients can accept concurrent chemoradiotherapy directly.

[Laparoscopic type C1 hysterectomy based on the anatomic landmark of the uterus deep vein and its branches for cervical cancer].

Objective: To introduce the laparoscopic type C1 hysterectomy based on the anatomic landmark of the uterus deep vein and its branched and to evaluate its feasibility and safety for cervical cancer and its effect to bladder function and to provide some reference to simplify the surgical procedures of laparoscopic type C1 hysterectomy. Methods: The clinicopathologic data of the patients with stage ⅠA2~ⅡB cervical cancer and who underwent the laparoscopic C1 hysterectomy based on anatomic landmark of the uterus deep vein and its branches between March 2010 and December 2015 was retrospectively analysed. Results: A total of 99 patients received laparoscopic type C1 hysterectomy based on the anatomic landmark of the uterus deep vein and its branches, in which 93 patients reserved unilateral or bilateral pelvic autonomic nerve successfully, the other 6 patients were transfered to receive type C2 hysterectomy due to adhesions, bleeding or the low possibility of curative resection. The failure rate of the surgery was 6.1% (6/99). The average age of these 93 patients was 44.4±8.2 years (range 25~61 years) and there was one case of stage ⅠA2, 84 stage ⅠB1, 2 stage ⅠB2, 5 stage ⅡA1 and 1 stage ⅡB. The number of patients with squamous cell carcinoma was 67, adenocarcinoma was 19, adenosquamous carcinoma was 3, small cell neuroendocrine carcinoma was 3 and mixed type was 1. The average operation time was 4.1±0.5 h, the average amount of intraoperative blood loss was 103.8±84.0 ml and the mean number of excisional pelvic lymph nodes was 29.7±8.9. There was no patient with positive parametrial margin, positive vaginal margin or intraoperative ureteral injury. The postoperative catheter extraction time was 20.3±8.4 d. The median follow-up time was 20 months (rang 5~44 months), the long-term bladder dysfunction rate was 8.6% (8/93). The numbers of locally uncontrolled and distantly metastasis case were both one and both patients died. The fatality rate were 2.2% (2/93). The two-year disease-free survival and overall survival rate were 97.6% and 96.2%, respectively. Conclusion: Laparoscopic type C1 hysterectomy based on the anatomic landmark of the uterus deep vein and its branches is a safe and feasible treatment method for cervical cancer and it provides a new approach for simplifying the surgical procedures of laparoscopic type C1 hysterectomy.

Treatment and outcome of Stage I Al squamous carcinoma of the cervix: a clinicopathologic study of 346 cases.

OBJECTIVE: To analyze the clinicopathologic feature of Stage I A I squamous carcinoma of the cervix (SCC) and to explore the outcome of different surgical methods. MATERIALS AND METHODS: Clinicopathological data of 346 cases with Stage I Al SCC diagnosed between November 2nd, 1995 and December 31st, 2011 were reviewed and analyzed. RESULTS: As major diagnostic method, 44.5% (154/346) patients accepted cold knife conization (CKC), while 58.1% (201/346) patient took total hysterectomy (TH) as their final surgical methods. The trend in treatment methods from 1995 to 2011 revealed that increasing cases were treated with CKC, modified radical hysterectomy (MRH) obviously reduced, while the proportion treated by TH remained unchanged. Due to a small number of cases receiving vaginal trachelectomy (VT) and radical trachelectomy (RT), the authors did not find any obvious changes. PROGNOSIS: The overall recurrence rate was 1.2% (4/346). The overall survival rates for CKC, VT, TH, MRH, and RT were 100%, 100%, 98.2%, 100%, and 100%, and the difference was not statistically significant (p = 0.819). The incidence rate of LVSI was 4.9% (17/346), the overall survival rates for patients with LVSI and without LVSI were 99.3% and 93.3%, respectively, and there was statistical difference between them (p = 0.003). Univariate analysis showed that only LVSI was an important predictor for survival (p = 0.030). CONCLUSIONS: the treatments for Stage I Al SCC are becoming more conservative, and individualized therapy and more frequent surveillance should be administrated to those patients with LVSI.

Orbital angular momentum entanglement via fork-poling nonlinear photonic crystals.

We report a compact scheme for the generation and manipulation of photon pairs entangled in the orbital angular momentum (OAM) from the fork-poling quadratic nonlinear crystal. The χ(2)-modulation in this crystal is designed for fulfilling a tilted quasi-phase-matching geometry to ensure the efficient generation of entangled photons as well as for transferring of topological charge of the crystal to the photon pairs. Numerical results show that the OAM of photon pair is anti-correlated and the degree of OAM entanglement can be enhanced by modulating the topological charge of crystal, which indicates a feasible extension to high-dimensional OAM entanglement. These studies suggest that the fork-poling nonlinear photonic crystal a unique platform for compact generation and manipulation of high-dimensional and high-order OAM entanglement, which may have potential applications in quantum communication, quantum cryptography and quantum remote sensing.

Concurrent optical parametric down-conversion in χ(2) nonlinear photonic crystals.

We experimentally investigated concurrent parametric downconversion processes in a two-dimensional hexagonally poled lithium tantalate crystal. The substantial enhancement of parametric gain was observed when concurrent processes shared a common parametric beam. Both degenerate and nondegenerate concurrent parametric downconversion processes were studied. Analyses of the spatial forms and output angles showed a strong dependence on the working temperature, during which a well-defined beamlike parametric output was observed. Our results will stimulate the design for coherent high-gain generation of multiple parametric beams and also shed light on the compact engineering of path-entanglement with specific spatial forms based on concurrent spontaneous parametric downconversion processes.

Diode-pumped 1988-nm Tm:YAP laser mode-locked by intracavity second-harmonic generation in periodically poled LiNbO3.

We report a diode-pumped intracavity second-harmonic generation mode-locked solid-state Tm:YAP laser operating at 1988 nm using a periodically poled congruent LiNbO3 as the nonlinear crystal. The threshold of continuous wave mode locking is 11.6 W. The maximum output power is 1.67 W, while the shortest pulse obtained is 4.7 ps at a repetition rate of 97.09 MHz.

On-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits.

A consequent tendency toward high-performance quantum information processing is to develop the fully integrated photonic chip. Here, we report the on-chip generation and manipulation of entangled photons based on reconfigurable lithium-niobate waveguide circuits. By introducing a periodically poled structure into the waveguide circuits, two individual photon-pair sources with a controllable electro-optic phase shift are produced within a Hong-Ou-Mandel interferometer, resulting in a deterministically separated identical photon pair. The state is characterized by 92.9±0.9% visibility Hong-Ou-Mandel interference. The photon flux reaches ∼1.4×10(7) pairs nm-1 mW-1. The whole chip is designed to contain nine similar units to produce identical photon pairs spanning the telecom C and L band by the flexible engineering of nonlinearity. Our work presents a scenario for on-chip engineering of different photon sources and paves the way to fully integrated quantum technologies.

Heralded generation of multipartite entanglement for one photon by using a single two-dimensional nonlinear photonic crystal.

We propose a compact scheme for the heralded generation of single-photon multipartite entanglement by using a single two-dimensional nonlinear photonic crystal. Studies have shown that by appropriate structure design, the single-photon entanglement shared among three spatially distinct optical modes can be generated through three concurrent spontaneous parametric down-conversion processes by using the other photon in an identical spatial mode as a trigger. Furthermore, we analyze the entanglement of such heralded single-photon tripartite W-type state theoretically. This method can be expanded for the heralded single-photon N-partite entanglement generation. This compact and stable quantum light source may act as a key ingredient in quantum information science.

Compact engineering of path-entangled sources from a monolithic quadratic nonlinear photonic crystal.

An integrated realization of photonic entangled states becomes an inevitable tendency toward integrated quantum optics. Here we report the compact engineering of steerable photonic path-entangled states from a monolithic quadratic nonlinear photonic crystal. The crystal acts as a coherent beam splitter to distribute photons into designed spatial modes, producing the heralded single-photon and appealing beamlike two-photon path entanglement. We characterize the path entanglement by implementing quantum spatial beating experiments. Such a multifunctional entangled source can be further extended to the high-dimensional fashion and multiphoton level, which paves a desirable way to engineering miniaturized quantum light sources.

Angle-dependent light emission from aligned multiwalled carbon nanotubes under CO(2) laser irradiation.

This paper reports the light emission from aligned multiwalled carbon nanotubes (MWNTs) under continuous wave CO(2) laser (λ = 10.6 µm) irradiation. Results indicate that the light emission is dependent on the angle θ between the laser incident direction and the nanotube axis. The relative intensity of the light emission at certain wavelengths shows a Lorentzian feature when θ varies from 0° to 90°. The Lorentzian fitting curve displays a distinct tendency between shorter (λ<600 nm) and longer wavelength (λ>700 nm). A minimum intensity was observed at θ(m) close to 67° under shorter wavelength, whereas a maximum intensity was shown at θ(m) of about 60° at longer wavelength. These results show the anisotropic property of aligned MWNTs.